In order to predict arrival of a tsunami or the like, a prediction using a tsunami forecast database (Non Patent Document 1) and a prediction using an observation of a wave using an ocean radar (Non Patent Document 2) have been used.
In the prediction using a tsunami forecast database described in Non Patent Document 1, a numerical simulation of a tsunami at each point of occurrence of a tsunami is conducted to predict a scale of the tsunami to reach a coastal area. In the prediction using the ocean radar described in Non Patent Document 2, a reflected wave of a radio wave emitted toward a sea surface is analyzed, and a speed of a wave and how the wave is to spread are estimated, to thereby predict the reaching of the tsunami.